There exist flutes, piccolos and generally wind instruments which possess a footjoint section which allows the instrument to play notes down to low B. Traditionally all of the footjoint keys are open with the exception of D#. And traditionally the low B key is closed only when playing low B and when playing C in the third octave.
Prior to Theobald Boehm, (Apr. 9, 1794-Nov. 25, 1881) the Bavarian inventor and musician, who perfected the modern flute and its improved fingering system, most flutes and piccolos had a tapered bore and included a small diameter of the taper at the foot of the instrument. This taper solved intonation problems associated with notes in the upper registers. Boehm changed this bore design and placed the taper at the headjoint end with the small diameter of the taper at the crown and additionally utilized a straight bore for the body. As such, the larger body improved projection and tone quality while the tapered headjoint simultaneously corrected intonation problems seen in earlier flutes. This basic layout has remained unchanged in modern flutes and some piccolos since Boehm's time.
Today, two genres of flute and piccolo bore designs exist in the art. The first category, found in some piccolos and most modern flutes, features a straight body and tapered headjoint. The second variety, found in most modern piccolos and all Baroque flutes, features a tapered body and straight bore headjoint.
What is needed is a footjoint section in which low B is normally closed and is opened only when low C is sounded. This improves the tone of the piccolo or flute in the third octave, especially high G#, high F# high B and high C. It makes playing the instrument easier because the low B key does not have to be pressed for notes in the third octave.
What is also needed is a flute or piccolo with a tapered bore in the body combined with a tapered bore in the headjoint to improve the intonation match between octaves even more than is possible with a tapered headjoint alone.